The present invention relates to an apparatus for applying a specified torque to a threaded backshell of a multipin electrical connector.
Electrical connectors used in aircraft and various types of military vehicles are generally environmentally sealed to prevent moisture incursion. Such connectors are of the type specified in military standards such as, for example, MIL-C-26482, -24308, -26500, -38999 or -5015 as well as numerous other military and industrial specs. In general, these connectors are multipin connectors in which the pins are releasably held in place in the connectors and in which an elastomer material fills the connector around at least a portion of the pins and the electrical wiring connected to the pins. The pins may be soldered or crimped to an electrical wire or cable and are inserted into the connector from the rear side by pushing the pins through preformed holes in the elastomer insert in the connector. The connectors include an outer metal housing with a keyed front section for mating engagement with another connector. A captured twist-lock member couples the two mating connectors. The back part of the housing is threaded for receiving a backshell. The backshell may include an extension for fastening about the wires exiting the rear of the connector for strain relief.
In assembling the backshell to the connector, the connector housing is coupled to a fixture which holds the housing in a fixed position. The backshell is then threaded onto the back of the connector and tightened with ring pliers. Because these connectors are commonly used in areas subject to significant and continuous vibration, the backshell must be tightened onto the connector housing with a specified torque to prevent loosening. One method used to measure applied torque is to attach a torque wrench to the fixture and use a coupling between the connector and wrench. As the backshell is tightened, the amount of torque is visible on the torque wrench.
One problem with the prior art system using ring pliers is that it is difficult for an operator to hold the handles of the pliers closed with sufficient force to keep a good grip on the connector backshell while at the same time attempting to turn the backshell with the pliers in order to develop the required holding torque. Still further, prior systems did not provide a method for easily determining when the specified torque was achieved such as by an audible click of a torque wrench.